export class HUD {
  constructor() {
    this.canvas = document.getElementById('hud-canvas');
    this.ctx = this.canvas.getContext('2d');
    this.visible = false;
  }

  show() {
    this.visible = true;
    document.getElementById('hud-overlay').style.display = 'block';
  }

  hide() {
    this.visible = false;
    document.getElementById('hud-overlay').style.display = 'none';
  }

  clear() {
    this.ctx.clearRect(0, 0, 320, 200);
  }

  draw(flightModel) {
    if (!this.visible) return;
    this.clear();
    const ctx = this.ctx;

    const speed = flightModel.getAirspeedKnots();
    const altitude = flightModel.getAltitudeFeet();
    const heading = flightModel.getHeadingDeg();
    const vsi = flightModel.getVerticalSpeedFtMin();
    const pitch = flightModel.getPitchDeg();
    const roll = flightModel.getRollDeg();
    const throttle = flightModel.thrust;

    // Artificial horizon (center-bottom)
    this.drawArtificialHorizon(ctx, pitch, roll);

    // Heading tape (top center)
    this.drawHeadingTape(ctx, heading);

    // Airspeed indicator (left side)
    this.drawAirspeed(ctx, speed);

    // Altimeter (right side)
    this.drawAltimeter(ctx, altitude);

    // Vertical speed indicator (right side, below altimeter)
    this.drawVSI(ctx, vsi);

    // Throttle indicator (bottom left)
    this.drawThrottle(ctx, throttle);

    // Heading number
    const cardinal = this.headingToCardinal(heading);
    ctx.fillStyle = '#00FF00';
    ctx.font = '8px "Press Start 2P", monospace';
    ctx.textAlign = 'center';
    ctx.fillText(`${Math.round(heading)}° ${cardinal}`, 160, 12);
  }

  drawArtificialHorizon(ctx, pitch, roll) {
    const w = 100;
    const h = 60;
    const x = 110;
    const y = 140;

    ctx.save();
    ctx.beginPath();
    ctx.rect(x, y, w, h);
    ctx.clip();

    const cx = x + w / 2;
    const cy = y + h / 2;

    ctx.translate(cx, cy);
    ctx.rotate(-roll * Math.PI / 180);

    const pitchOffset = pitch * 1.5;

    // Sky
    ctx.fillStyle = '#0000AA';
    ctx.fillRect(-60, -40 + pitchOffset, 120, 40);

    // Ground
    ctx.fillStyle = '#8B4513';
    ctx.fillRect(-60, pitchOffset, 120, 40);

    // Horizon line
    ctx.strokeStyle = '#FFFFFF';
    ctx.lineWidth = 1;
    ctx.beginPath();
    ctx.moveTo(-60, pitchOffset);
    ctx.lineTo(60, pitchOffset);
    ctx.stroke();

    // Pitch lines
    ctx.strokeStyle = '#FFFFFF88';
    ctx.lineWidth = 1;
    for (let p = -20; p <= 20; p += 10) {
      if (p === 0) continue;
      const py = p * 1.5;
      ctx.beginPath();
      ctx.moveTo(-10, py);
      ctx.lineTo(10, py);
      ctx.stroke();
    }

    ctx.restore();

    // Aircraft reference symbol
    ctx.strokeStyle = '#FF8800';
    ctx.lineWidth = 2;
    ctx.beginPath();
    ctx.moveTo(cx - 18, cy);
    ctx.lineTo(cx - 6, cy);
    ctx.stroke();
    ctx.beginPath();
    ctx.moveTo(cx + 6, cy);
    ctx.lineTo(cx + 18, cy);
    ctx.stroke();
    ctx.beginPath();
    ctx.moveTo(cx, cy);
    ctx.lineTo(cx, cy + 3);
    ctx.stroke();

    // Border
    ctx.strokeStyle = '#00FF00';
    ctx.lineWidth = 1;
    ctx.strokeRect(x, y, w, h);
  }

  drawHeadingTape(ctx, heading) {
    const y = 22;
    const ctx2 = ctx;

    ctx2.fillStyle = 'rgba(0, 0, 0, 0.5)';
    ctx2.fillRect(80, 14, 160, 18);
    ctx2.strokeStyle = '#00FF00';
    ctx2.lineWidth = 1;
    ctx2.strokeRect(80, 14, 160, 18);

    ctx2.font = '6px "Press Start 2P", monospace';
    ctx2.textAlign = 'center';
    ctx2.fillStyle = '#00FF00';

    const cards = [
      { deg: 0, label: 'N' },
      { deg: 90, label: 'E' },
      { deg: 180, label: 'S' },
      { deg: 270, label: 'W' },
    ];

    cards.forEach(({ deg, label }) => {
      const diff = heading - deg;
      const px = (diff / 30) * 8;
      const lx = 160 + px;
      if (lx > 85 && lx < 235) {
        ctx2.fillText(label, lx, y);
      }
    });
  }

  drawAirspeed(ctx, speed) {
    const x = 8;
    const y = 40;
    const w = 30;
    const h = 100;

    ctx.fillStyle = 'rgba(0, 0, 0, 0.5)';
    ctx.fillRect(x, y, w, h);
    ctx.strokeStyle = '#00FF00';
    ctx.lineWidth = 1;
    ctx.strokeRect(x, y, w, h);

    // Speed bar
    const fill = Math.min(1, speed / 200);
    const barH = fill * (h - 10);
    ctx.fillStyle = fill > 0.85 ? '#FF5555' : fill > 0.6 ? '#FFFF55' : '#00FF00';
    ctx.fillRect(x + 2, y + h - 4 - barH, w - 4, barH);

    // Speed ticks
    ctx.fillStyle = '#00FF00';
    ctx.font = '6px "Press Start 2P", monospace';
    ctx.textAlign = 'left';
    for (let s = 0; s <= 200; s += 50) {
      const tickY = y + h - 4 - (s / 200) * (h - 10);
      ctx.fillRect(x, tickY - 0.5, 4, 1);
    }

    // Current speed
    ctx.textAlign = 'center';
    ctx.font = '8px "Press Start 2P", monospace';
    ctx.fillText(Math.round(speed), x + w / 2, y - 4);
    ctx.font = '5px "Press Start 2P", monospace';
    ctx.fillText('KT', x + w / 2, y + h + 10);
  }

  drawAltimeter(ctx, altitude) {
    const x = 282;
    const y = 40;
    const w = 30;
    const h = 100;

    ctx.fillStyle = 'rgba(0, 0, 0, 0.5)';
    ctx.fillRect(x, y, w, h);
    ctx.strokeStyle = '#00FF00';
    ctx.lineWidth = 1;
    ctx.strokeRect(x, y, w, h);

    // Altitude bar
    const fill = Math.min(1, altitude / 15000);
    const barH = fill * (h - 10);
    ctx.fillStyle = '#00FF00';
    ctx.fillRect(x + 2, y + h - 4 - barH, w - 4, barH);

    // Current altitude
    ctx.fillStyle = '#00FF00';
    ctx.font = '8px "Press Start 2P", monospace';
    ctx.textAlign = 'center';
    ctx.fillText(Math.round(altitude), x + w / 2, y - 4);
    ctx.font = '5px "Press Start 2P", monospace';
    ctx.fillText('FT', x + w / 2, y + h + 10);
  }

  drawVSI(ctx, vsi) {
    const x = 282;
    const y = 155;
    const w = 30;
    const h = 35;

    ctx.fillStyle = 'rgba(0, 0, 0, 0.5)';
    ctx.fillRect(x, y, w, h);
    ctx.strokeStyle = '#00FF00';
    ctx.lineWidth = 1;
    ctx.strokeRect(x, y, w, h);

    ctx.fillStyle = '#00FF00';
    ctx.font = '6px "Press Start 2P", monospace';
    ctx.textAlign = 'center';
    const vsiText = vsi >= 0 ? `+${Math.round(vsi)}` : Math.round(vsi);
    ctx.fillText(vsiText, x + w / 2, y + 14);
    ctx.font = '5px "Press Start 2P", monospace';
    ctx.fillText('FT/M', x + w / 2, y + 26);
  }

  drawThrottle(ctx, throttle) {
    const x = 8;
    const y = 160;
    const w = 40;
    const h = 8;

    ctx.fillStyle = 'rgba(0, 0, 0, 0.5)';
    ctx.fillRect(x, y, w, h);
    ctx.strokeStyle = '#00FF00';
    ctx.lineWidth = 1;
    ctx.strokeRect(x, y, w, h);

    const fill = throttle * (w - 2);
    ctx.fillStyle = throttle > 0.8 ? '#FF5555' : '#00AAAA';
    ctx.fillRect(x + 1, y + 1, fill, h - 2);

    ctx.fillStyle = '#00FF00';
    ctx.font = '5px "Press Start 2P", monospace';
    ctx.textAlign = 'left';
    ctx.fillText('THR', x, y - 3);
  }

  headingToCardinal(deg) {
    const dirs = ['N', 'NNE', 'NE', 'ENE', 'E', 'ESE', 'SE', 'SSE',
      'S', 'SSW', 'SW', 'WSW', 'W', 'WNW', 'NW', 'NNW'];
    const idx = Math.round(deg / 22.5) % 16;
    return dirs[idx];
  }
}